Garella R, Idrizaj E, Traini C, Squecco R, Vannucchi MG, Baccari MC. Glucagon-like peptide-2 modulates the nitrergic neurotransmission in strips from the mouse gastric fundus.
World J Gastroenterol 2017;
23:7211-7220. [PMID:
29142468 PMCID:
PMC5677198 DOI:
10.3748/wjg.v23.i40.7211]
[Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/19/2017] [Accepted: 09/26/2017] [Indexed: 02/06/2023] Open
Abstract
AIM
To investigate whether glucagon-like peptide-2 (GLP-2) influences the neurally-induced responses in gastric strips from mice, since no data are available.
METHODS
For functional experiments, gastric fundal strips were mounted in organ baths containing Krebs-Henseleit solution. Mechanical responses were recorded via force-displacement transducers, which were coupled to a polygraph for continuous recording of isometric tension. Electrical field stimulation (EFS) was applied via two platinum wire rings through which the preparation was threaded. The effects of GLP-2 (2 and 20 nmol/L) were evaluated on the neurally-induced contractile and relaxant responses elicited by EFS. Neuronal nitric oxide synthase (nNOS) enzyme was evaluated by immunohistochemistry.
RESULTS
In the functional experiments, electrical field stimulation (EFS, 4-16 Hz) induced tetrodotoxin (TTX)-sensitive contractile responses, which were reduced in amplitude by GLP-2 (P < 0.05). In the presence of the nitric oxide (NO) synthesis inhibitor L-NNA, GLP-2 no longer influenced the neurally-evoked contractile responses (P > 0.05). The direct smooth muscle response to methacholine was not influenced by GLP-2 (P > 0.05). In the presence of guanethidine and carbachol, the addition of GLP-2 to the bath medium evoked TTX-sensitive relaxant responses that were unaffected by L-NNA (P > 0.05). EFS induced a fast NO-mediated relaxation, whose amplitude was enhanced in the presence of the hormone (P < 0.05). Immunohistochemical experiments showed a significant increase (P < 0.05) in nNOS immunoreactivity in the nerve structures after GLP-2 exposure.
CONCLUSION
The results demonstrate that in gastric fundal strips, GLP-2 influences the amplitude of neurally-induced responses through the modulation of the nitrergic neurotransmission and increases nNOS expression.
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